Technical Abstract:
Fruit coatings have been shown to provide significant mortality to fruit fly immatures inside of fruits and have combined positively with other quarantine treatments. Coatings vary in toxicity to fruit fly immatures in fruits. Although levels of mortality as high as 100% of Caribbean fruit fly in grapefruits (Sta-Fresh 600) have been reached in tests, it seems unlikely that a coating by itself would be sufficient to provide complete quarantine security against fruit flies. Grapefruits infested with Mexican fruit fly and coated with Nature Seal 2020 (a moderately toxic coating) resulted in 54% mortality to eggs and early instars and only 12% to third instars. However, the surprisingly high (>90%) levels of mortality found with some coatings suggest that they may be combined with other treatments to produce quarantine security or incorporated into quarantine security systems where each component of the system reduces the risk of pest introduction. Hot air treatments could be shortened considerably if the fruit were coated prior to treatment. Complete Caribbean fruit fly mortality in coated grapefruits treated with forced hot air at 48 deg C was achieved after one hour versus > hours for uncoated grapefruits. The Florida Department of Agriculture is studying the possibility of incorporating coatings into the Caribbean fruit fly-free protocol for grapefruits shipped to Japan. Coatings may also work with other internal pests, quarantine treatments, and commodities and should be further studied.